The Practice of

Minimally Invasive Spinal Technique

Martin H Savitz, John C. Chiu,

Wolfgang Rauschning Anthony T. Yeung

The Practice of Minimally Invasive Spinal Technique

2005 Edition

The Practice of Minimally Invasive Spinal Technique

2005 EDITION

Editors-in-Chief

Martin H Savitz, M.D., Ph.D., F.A.C.S., F.I.C.S., F.R.C.S. (US) Executive Director, American Academy of Minimally Invasive Spinal Specialists Provost and Dean American International University John C. Chiu, M.D., D.Sc., F.R.C.S. (US), F.I.C.S. Chief of Neurospine Surgery, President, California Spine Institute, Founding Chairman, American Academy of Minimally Invasive Spinal Medicine and Surgery; Wolfgang Rauschning, M.D., Ph.D. Research Professor of Clinical and Applied Anatomy and Pathology, Professor of Orthopaedics, Uppsala University Hospital, Sweden. Anthony T. Yeung, M.D., F.A.B.M.I.S.S. Chief Surgeon, Arizona Institute for Minimally Invasive Spine Care, Associate Clinical Professor of Orthopedics, University of California, San Diego, California Editors

Benjamin Alli, M.D., Ph.D., M.P.H., F.R.C.P.(US), F.R.C.S.(US) Chairman of the Board and Dean, American International University

Merrill W. Renter, M.D., Ph.D., M.M.S., F.A.C.P.S., F.A.B.M.I.S.S. Professor of Orthopaedics, American International University Sang-Ho Lee, M.D., Ph.D., F.A.B.M.I.S.S., F.R.C.S.(US) Professor of Neurosurgery, American International University Solomon Kamson, M.D., Ph.D., F.A.B.I.P.M., F.R.C.S.(US) Associate Professor of Pain Management American International University Robert S. Mathews, M.D., Ph.D., F.A.C.S., F.I.C.S., F.R.C.S.(US) Professor of Orthopaedics, American International University

American Academy of Minimally Invasive Spinal Medicine and Surgery

Richmond, VA: AAMISMS Education, [2006]

The Practice of Minimally Invasive Spinal Technique

LIST OF CONTRIBUTORS David R Adin, DO Physiatrist, Department of Rehabilitation, Hospital for Special Surgery, New York, New York Benjamin Alli, M.D., Ph.D., M.P.H., F.R.C.P.(US), F.R.C.S.(US) Chancellor, Royal College of Physicians & Surgeons (US); Chairman of the Board, Dean of Medical Research, Professor of Clinical Medicine, American International University, Chairman. American Council for Board Certification Javier Ahrarado, M.D. Practicing Orthopedist, Advanced Orthopaedics of South Florida Diane M. Anger, B.S. Advanced Orthopaedics of South Florida Haq Babur, M.D., F.J.C.S., EA.B.M.I.S.S., F.R.C.S.(US) Assistant Clinical Professor, Department of Surgery, University of New Mexico School of Medicine, Albuquerque, New Mexico lchalid A. Batterjee, M.D., F.A.B.M.I.S.S. President, German-Saudi Hospital Group, Jedda, Kingdom of Saudi Arabia; President, Middle East Spine Group Joyce Bockar, M.D. Psychiatrist, Stamford, Connecticut Christopher M. Bono, M.D. Department of Orthapaedic Surgery, Boston University School of Medicine, Boston, Massachusetts Pedro A. Bravo-Bernabe, M.D. Attending Orthopedist, General Hospital of Mexico, Mexico City, Mexico Elizabeth Breen, Ph.D. Hunton & William, Richmond, Virginia Jasip Buric, M.D. Department of Minimally Invasive Spine Surgery, University of Villanova Florence, Italy Lucia Carlucci, Ph.D., D.Sc. ADITUS Systems, Laguna Hills, California William J. Canoll, M.S. Arizona Institute for Minimally Invasive Spine Care, Phoenix, Arizona Joan L. Carter, R.N. Ellman Innovations, Oceanside, New York

Sang Burn Chang, M.D. Wooridul Spine Hospital, Seoul, Korea David Chatenever Karl Storz Imaging, Inc., Goleta, California Anne M. Chicorelli, D.0. Practicing Osteopath, Philadelphia, Pennsylvania John C. Chin, M.D., D.Sc., F.R.CS.(US), F.LCS. Founding Chairman, American Academy of Minimally Invasive Spinal Medicine and Surgery; Chief of Neurospine Surgery, President, California Spine Institute, Thousand Oaks, California Byung Kwan Choi, M.D., Ph.D. Wooridul Spine Hospital, Seoul, Korea SeokminChoi, M.D., PhD. Wooridul Spine Hospital, Seoul, Korea Won-Cheol Choi, M.D., F.A.B.M.I.S.S., F.R.C.S.(US) Wooridul Spine Hospital, Seoul, Korea Thomas J. Clifford, M.D., F.A.B.M.I.S.S. Neurospine Surgeon, California Spine Institute, Thousand Oaks, California Ronald L.L. Collins, M.D., F.R.CS. Attending Neurosurgeon, New York, New York Jevan Damadian, B.S.E.E. FONAR Corporation, Melville, New York Raymond V. Damadian, M.D., D.Sc. FONAR Corporation, Melville, New York Ninel V. Dedukh, M.D. Syntenko Institute of Bone and Joint Pathology, Academy of Medical Sciences, Kharkow, Ukraine Bradley N. Delman, M.D. Assistant Professor of Radiology. Section of Neuroradiology, The Mount Sinai School of Medicine, New York, New York Jean Destandau, M.D. Chief of Neurosurgery, Hopital Bagatelle, Talence, France Akira Dezawa, M.D., Ph.D. Professor of Orthopaedics, University of Teikyo School of Medicine, Kawasaki, Japan C. John DiGregorio, M.D., Ph.D. Professor Emeritus, Department of Pharmacology, Drexel University, School of Medicine, Philadelphia, Pennsylvania Joseph K. DiPalma, M.D., D.Sc.(HON) Professor Emeritus, Department of Pharmacology, Drexel University, School of Medicine Philadelphia, Pennsylvania

Jay S. Dworkin, Ph.D. FONAR Corporation, Melville New York Janet Fleetwood Ph.D. Associate Professor and Chief Medical Humanities Division Drexel University, School of Medicine, Philadelphia, Pennsylvania - Stephanie J. Foecht, M.S. Department of Pharmacology, Drexel University, School of Medicine, Philadelphia, Pennsylvania Edmund Frank, M. D. Oregon Health Science University, Department of Neurological Surgery, Portland, Oregon Joannis N. Gaitanis, M. D. Department of Orthopaedic Surgery, University of Kriti, Kriti, Greece Steven R. Garfin, M.D. Professor and Chairman, Department of Orthopaedics, University of California, San Diego, California Mark Gelbien FONAR Corporation, Melville, New York Mary Gianni, R.T. FONAR Corporation, Melville, New York Richard T. Goldberg, Ph.D. Harvard Medical School, Boston, Massachusetts Gaspar Gonzales-Astudillo, M.D. Attending Orthopedist, General Hospital of Mexico, Mexico City, Mexico Gary V. Gordon, M.D., F.A.C.P., F.A.C.R. Clinical Associate Professor, Department of Medicine, Thomas Jefferson College of Medicine, Philadelphia, Pennsylvania Robert C. Gordon, D.C., F.A.B.C.S., F.R.C.C.M. Co-Chairman, American Board of Chiropractic Specialists C. A. Green FONAR Corporation, Melville, New York John. F. Greenhalgh, Ph.D. FONAR Corporation, Melville, New York Alexander C. Hadjipavlou, MD. Professor and Chairnan of Orthopaedic Surgery, University of Kriti, Kriti, Greece John W. Hailer, Ph.D. Department of Radiology and Division of Neurosurgery, University of Iowa, Iowa City, Iowa Ahmed Hamdy, M.D. Department of Orthopedics and General Surgery, Am Shams University, Cairn, Egypt Johannes Hellinger, M.D. Nova Med Hospital, Munich, Germany

Stefan Hellinger, M.D. Nova Med Hospital, Munich, Germany Braulilo Hernandez-Carbajal, MD. Attending Orthopedist, General Hospital of Mexico, Mexico City Mexico Benjamin Hoch, M.D. Assistant Professor of Pathology, The Mount Sinai School of Medicine, New York, New York Thomas Hoogland, M.D. Director, Alpha Klinic, Munich, Germany H.K. Huang D.Sc., F.R.C.R(HON) Professor of Informatics, University of Southern California, Los Angeles, California Vladimir A. Iakomi, M.D., F.R.C.S.(US) Attending Surgeon, Penn Surgery Institute, Lancaster, Pennsylvania Gary Jacob, D.C. Practicing Chiropractor, Los Angeles, California Sang Hyeop Jeon, M.D. Woodrul Hospital, Seoul, Korea J. Randy Jinkins, AD, F.A.C.R. Professor of Radiology, Downstate Medical Center, State University of New York, Brooklyn, New York; Senior Research Fellow, FONAR Corporation, Melville, New York Panriz Kambin, M.D. Professor Emeritus of Orthopaedics, Drexel University, School of Medicine, Philadelphia, Pennsylvania; Founding Chairman, International Society for Minimal Intervention in Spinal Surgery Solomon Kamson, M.D., Ph.D., F.A.B.I.P.M., F.R.C.S.(US) Assistant Clinical Professor, Department of Anesthesia and Health Sciences, University of Washington, Seattle, Washington; Associate Professor of Pain Management American International University Sri Kantha, M.D., F.A.B.I.P.M., F.R.C.S.(US) Professor of Pain Management American International University, Director New Jersey Center For Pain Management, Fort Lee, New Jersey Atac Karakas, M.D. University of Ankara School Ibni Sina Hospital, Department of Orthopedics and Traumatology, Samanpazai, Ankara, Turkey Pavios G Katonis, MD Department of Orthopaedic Surgery University of Kriti, Kriti Greece Scott Katzman, M D Advanced Orthopaedic Sports Medicine, Ft. Pierce, Florida P. Douglas Kiester, M.D, F.A.C.S Chairman and Professor, Department of Orthopaedics, University of California, Irvine, California

Won Joong Kim, M.D., Ph.D. Wooridul Hospital, Seoul, Korea Martin T.N. Knight, F.R.C.S. Director, Spinal Foundation, Arbury Consulting Centre, Rothdale, United Kingdom Anthony C.K. Lau, M.D., F.A.C.A. Practicing Acupuncturist, New City, New York Ho-Yeon Lee, M.D., Ph.D., F.A.B.M.I.S.S., F.R.C.S.(US) Wooridul Hospital, Seoul, Korea Sang-Ho Lee, M.D., Ph.D., F.A.B.M.I.S.S., F.R.C.S.(US) Professor of Neurosurgery, American International University; Executive Committee, American Board of Minimally invasive Spinal Surgery; President, Wooridul Spine Hospital, Seoul, Korea Zinovy Lekht, M.D. California Spine Institute, Thousand Oaks, California Hansjoerg F. Leu, M.D. Professor of Orthopaedics, Bathania Hospital, Zurich, Switerland Soo Taek Lim, M.D., F.A.B.M.I.S.S., F.R.C.S.(US) Wooridul Hospital, Seoul, Korea Manuel L. Lipson, M.D. Clinical Associate Professor of Medicine, Harvard Medical School, Boston, Massachusetts Liu Shang-Li, M.D. Spine and Joint Unit, Department of Orthopedics, the Second Affiliated Hospital of Henan Medical University Zhengzhou Peoples Republic of China Karen E. Locker, M.D Department of Anesthesia, Good Samaritan Hospital, Lebanon, Pennsylvania Gregory E. Lutz, M.D. Department of Anesthesia, Hospital for Special Surgery, New York, New York Leonard L Malls, M.D., Ph.D.(HON) Professor Emeritus of Neurosurgery, The Mount Sinai School of Medicine, New York, New York SvetlanaY. Malshkina, Ph.D. Sytenko Institute of Bone and Joint Pathology, Academy of Medical Sciences, Kharkov, Ukraine Robert S. Mathews, M.D., Ph.D., F.A.C.S., F.I.C.S., F.R.C.S.(US) Vice-President and Professor of Orthopaedics, American International University; Vice-President Royal College of Physicians & Surgeons of the United States; Chairman, American Board of Minimally invasive Spinal Surgery; Director, Penn Surgery Institute, Lancaster, Pennsylvania Mohamed A. Maziad, M.D., F.R.C.S. (US) Department of Orthopedics and General Surgery, in Shams University, Cairo, Egypt Carol M. McFarland, P.T., M.S. Physical Therapist, Tyler, Texas Michael Meriwether, M.D., Ph.D. Meriwether Center, Sarasota, Florida

Samir Mehta, M.D. Practicing Pain Management Specialist, RSZ Sports & Spine Center; Hospital of the University of Pennsylvania, Philadelphia; Pennsylvania Matthew R. Miller, R.N., PA., D.Sc., F.R.C.Sc. Clinical Instructor, Department of Orthopaedics, American International University; Physician Assistant, Penn Surgery Institute, Lancaster, Pennsylvania Michael Miller, D.O., M.Ch., F.A.C.O.S., F.A.B.W.C. Chairman, American Board of Wound Care Greg T. Mogel, M.D. Professor of Radiology, University of Southern California School of Medicine, Los Angeles California; Director West Telemedicine and Advanced Technology Research Center, US Army, Medical Research Command Vert Mooney, M.D. Professor Emeritus of Orthopedics, Department of Orthopedics, University of California at San Diego; Medical Director, US. Spine & Sport, San Diego, California Mark Morningstar, D.C Practicing Chiropractor, Pettibon Institute, Tacoma, Washing Thomas P. Naidich, M.D. Professor of Radiology. Section of Neuroradiology, The Mount Sinai School of Medicine, New York, New York Evguen G. Pedackenko, M.D. Professor of Neurosurgery Institute of Neurosurgery, Kiev, Ukraine Rodney H. Peterson, M.D. Pettibon Institute, Tacoma, Washington Burl R Pettibon, D.C., F.A.B.S., F.R.C.C.M President Pettibon Institute Tacoma Washington Lecturer, Palmer College of Chiropractic Davenport, Iowa; Lecturer, Cleveland Chiropractic College, Cleveland, Ohio; Lecturer, Parker College of Chiropractic, Dallas, Texas; Lecturer, Life University, Marietta, Georgia John Porter, M .D., F.A.B.I.P.M Practicing Pain Management Specialist, Arizona Institute for Minimally Invasive Spine Care, Phoenix, Arizona Robert Princenthal, M.D. F.A.B.I.P.M Practicing Neuroradiologist, California Spine Institute, Thousand Oaks, California Vladimir A Radchenko, M.D. Sytenko Institute of Bone and Joint Pathology, Academy of Medical Sciences, Kharkov, Ukraine. Jorge Ramirez, M.D. Director, Spine Department, Reina Sofia Clinic; Director, Spine Surgery Fellowship, University El Bosque, Bogota, Colombia Wolfgang Rauschning M.D., Ph.D. Research Professor of Clinical and Applied Anatomy and Pathology, Professor of Orthopaedics, Uppsala University Hospital, Sweden

Charles D. Ray, M.S., M.D., F.A.CS. President, American College of Spine Surgery; Past President, International Spine Arthroplasty Society; Past President, North American Spine Society K. Dean Reeves, M.D. Penn Surgery Institute, Lancaster, Pennsylvania Carol Remz, Ph.D. Director of Education, Pettibon Institute, Tacoma, Washington Merrill W. Renter, M.D., Ph.D., M.M.S., F.A.C.P.S., F.A.B.M.I.S.S. Assistant Clinical Professor of Biomedical Science, University of Miami School of Medicine, Miami, Florida; Associate Professor of Orthopaedics, American International University;. Chairman, American College of Physicians & Surgeons; President, Advanced Orthopaedics of South Florida S. M. Rezaian, M.D., Ph.D. Practicing Orthopedist, Beverly Hills, California Robin Saunders Ryan, M.S., P.T. Physical Therapist, Saunders Group, Chaska, Minnesota Timothy C. Ryken, M.D. Department of Radiology and Division of Neurosurgery, University of Iowa, Iowa City. Iowa Abmed Saeed, M.D. Department of Orthopaedics and General Surgery, Ain Shams University, Cairo, Egypt Joseph Salamone, D.C., F.A.B.C.S., F.R.C.C.M. Secretary, American Board of Chiropractic Specialists H. Duane Saunders, M.S., P.T. Physical Therapist, Saunders Group, Chaska, Minnesota Melissa Savenko, J.D. Hunton & Williams, Richmond, Virginia Martin H. Savitz, M.D., Ph.D., F.A.C.S., F.I.C.S., F.R.C.S.(US) Provost, Dean of Surgical Research, Professor of Neurosciences, American International. University; Vice-Chancellor, Royal College of Physicians & Surgeons (US); Executive Director, American Council for Board Certification, American Academy of Minimally Invasive Spinal Medicine and Surgery, and American Academy of Minimally Invasive Spinal Specialists 1 Sean I. Savitz, M.D. Assistant Professor, Department of Neurology, Harvard Medical School, Boston, Massachusetts Stanton Schiffer, M.D., F.A.B.M.I.S.S. University of California School of Medicine, San Francisco, California Fernando Schmidt, M.D. Clinica de Neurocirurgia, Porto Alegre, Brazil Gabriel E. Sella, M.D. M.P.H., Ph.D.(HON) Department of Community Medicine, West Virginia Univeristy, Morgantown, West Virginia Joseph C. Serrato, Jr., M.D., Ph.D.(HON), F.I.C.S., F.R.C.S.,(US), F.A.A.N.O.S. Board of Directors, United States Sports Academy; President, American International University

Lewis S. Sharps, M.D., F.A.C.S. Practicing Pain Management Specialist, RSZ Sports & Spine Center, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania Stephen Shaw, M.D. California Spine Institute, Thousand Oaks, California Chan Shik Shim, M.D., Ph.D., F.A.B.M.I.S.S., F.R.C.S.(US) Wooridul Spine Hospital, Seoul, Korea Sang-Woo Shin, M.D., Ph.D. Wooridul Spine Hospital, Seoul, Korea James W. Simmons, Jr., M.D. Clinical Professor, Division of Spine Surgery, Department of Orthopaedics and Rehabilitation, University of Texas, Galveston, Texas Romulo Sison, P.A. Physician Assistant California Spine Institute Thousand Oaks, California Jonas M. Sokolof, D.O. Harvard Medical School, Boston, Massachusetts Michael T. Stechison, M.D., Ph.D., F.R.C.S. Practicing Neurosurgeon, Greater Atlantic Neurosurgery, Atlanta, Georgia Michael A.Steingart, D.0. FA.B.M.I.S.S Osteopathic Orthopedic Specialist, Phoenix Arizona Aubrey A. Swartz, M. D., Pharm. D. Executive Director American Back Society Alaa E.D.M. Talaat, M.S., M.B.B.Ch. - Department of Orthopedics and General Surgery, Ain Shams University, Cairo, Egypt Frank Tilaro, M.D. Practicing Internist, Ogden, Utah Michael N. Tzermiadianos, M.D. Department of Orthopaedic Surgery, University of Kriti, Kriti, Greece Michael W. Vannier, M.D. Department of Radiology and Division of Neurosurgery, University of Iowa, Iowa City, Iowa. Kenneth C. Varley, M.D., F.RCP. (C) Southern Pain Specialists, Birmingham, Alabama Dieter Werner, M.D. Incura Klinic, Schmalkalden, Germany Daniel West, D.C., F.A.B.C.S., F.R.C.C.M.. CO-Chairman, American Board of Chiropractic Specialists Michael Witworth, M.D., F.A.B.I.P.M. Chairman, American Board of Interventional Pain Management

Robert B. Wolf, B.S. FONAR Corporation, Melville, New York Craig R. Wolff, M.D. Chief of Spine Surgery LASERSCOPIC Spine Centers of America Inc., St Petersburg, Florida Robert D. Wood, M.D., M.P.H. Professor of Anesthesia, University of Southern California School of Medicine, Los Angeles, California; Chief of Anesthesia, California Spine Institute, Thousand Oaks, California Tarik Yazar M.D. University of Ankara School Ibni Sina Hospital, Department of Orthopedics and Traumatology, Samanpazari, Ankara, Turkey Anthony T. Yeung, M.D., F.A.B.M.I.S.S. President, International Intradiscal Therapy Society; Associate Clinical Professor of Orthopedics, University of California, San Diego, California; Chief Surgeon, Arizona Institute for Minimally Invasive Spine Care, Phoenix, Arizona Christopher A. Yeung, M.D. Clinical Instructor of Orthopedics, University of California, San Diego, California; Practicing Orthopedist, Arizona Institute for Minimally Invasive Spine Care, Phoenix, Arizona Cengiz Yilmaz, MD. University of Ankara School Ibni Sina Hospital, Department of Orthopedics and Traumatology, Sanianpazari, Ankara, Turkey Zheng Zhaomin, M.D. Associate Professor and Director, Spine and Joint Unit, Department of Orthopedics, Affiliated Hospital of Henan Medical University, Zhengzhou, Peo

Chapter 35

VERTEBRAL AXIAL DECOMPRESSION

Figure1. VAX-D Table with patient position for decompression

Introduction Reduction of nuclear protrusion by spinal distraction was practiced even before the intervertebral disc was recognized. A 14th Century translation of Albucasia’s Surgery illustrates lumbar manipulation during spinal traction 12. Appolonius of Kitium describes a form of distraction 2000 years ago. Guidi (1544) illustrates a traction table in his Cirugia, and one of his tables can be found in the Wellcome Historical Museum of London. In their book on manipulation past and present, Cyriax and Schotz 18 illustrate the employment of traction by Hippocrates (400 BC), Galen (131-202 AD), and the Spanish-Arabian physician Abu’ L Qasim (1013-1106). Today, two methods of performing traction are practiced – the sustained manner preferred by Cyriax and various forms of intermittent traction. Intermittent traction can be done electronically, manually (therapist), or by the patient (autotraction). The effects of sustained traction have been investigated. An increase in body length of 10-30 mm was demonstrated in healthy males when a sustained force of 60kg was applied for 1 hour and was lost at 4mm/hr. 23 In the excised spine the greatest separation was in those subjects with wide disc spaces and least where there is evidence of disc degeneration. Other investigators confirmed an increase in stature

over and above that known to occur when the load is taken off the spine by lying down.2 The findings suggest that most of the vertebral separation takes place within the first 30 minutes. During normal traction, the enlargement between two consecutive lumbar endplates is between 1.0 and 1.5 mm. Other studies have demonstrated a widening of the lumbar intervertebral space of between 3 to 8 mm measured radiographically due to gravitational traction.10,20 Anderson et al have shown an increase in intradiscal pressure with certain traction techniques. The heavy lumbar paravertebral muscles exert resistance to distraction, and at least 30-35kg of force is required to influence the lumbar spine.10 Others have shown that a force of at least 25% of body weight is necessary to achieve lumbar distraction. With the split table, designed by Dr. Allan Dyer, he demonstrated that 25% of the traction force is required for distraction to occur. The effects of distraction include tightening of the posterior longitudinal ligament which exerts a centripetal force at the back of the joint. This maneuver may be of therapeutic value, particularly if the protrusion is located anterior and remains in close contact with the ligament. On the basis of biomechanical calculations significant intradiscal negative pressure may be achieved during sustained traction. 5 One study has shown that a traction load of 30 kg causes intradiscal pressure to lower from 30 kp to 10 kp in the L3 intervertebral disc. Improvement in nutrition and deposition of reparative collagen and healing of annular tears and fissures has been suggested as a benefit of axial distraction. Dr. Allan Dyer, former Deputy Minister of Health from Ontario, Canada a pioneer in the development of the external cardiac defibrillator, designed the VAX-D Therapeutic Table to apply distraction tension to the patient's spine without eliciting reflex paravertebral muscle contractions. A harness is attached to a tensionometer during separation of the movable pallet of the table. The distraction-relaxation cycles are automated or variable. Distraction tensions and rates are continuously monitored and measured by the tensionometer, and the output is shown on a digital gauge and captured on written printout. Procedure The VAX-D Table utilizes pneumatic cylinders coupled with hydraulic damping, as the drive/damping mechanism for the pretension and the program. The technology applies and maintains a baseline tension of 20 pounds (the pretension) to the patient’s pelvis throughout the treatment (even during the rest periods) and the distraction cycles then move from the pretension level up to a pre-selected therapeutic tension. The above processes are absolutely critical to the success of the treatment. The pneumatic drive cylinders separate the lower table section from the upper section and apply tension to the patient's pelvis. The pneumatic/hydraulic drive mechanism provides for a precise control of the amount of tension and is able to apply the force in a logarithmic time/force curve. The pneumatic/hydraulic drive mechanism is applied in both the distraction and retraction movements of the VAX-D Table, and provides a smooth controlled operation with gradual return of the pallet to the starting position each time. To achieve optimum control of the applied distractive tensions, it was found essential to develop a harness that would attach directly to an electronic tensionometer that continuously monitors and provides feedback of the tensions being applied to the spinal column. The harness design also facilitates proper placement necessary to attain reproducible results. Patients with discogenic low back pain with or without radiculopathy, who have failed conventional therapy, after 6-8 weeks are candidates for VAX-D therapy.21 Patients with

Figure 2. Note phases of pretension, tension ramping up, and desired tension stabilized on chart recording during treatment cycle of VAX-D.

neurological deficits are also candidates since outcome studies have shown no difference with surgical or medical management.9 Patient with fusion or failed back surgery syndrome are also candidates. Contraindications for VAX-D therapy include infection, neoplasm, osteoporosis, bilateral pars defect, unstable grade-2 spondylolysthesis, fractures, and the presence of surgical hardware in the spine. The patient should be evaluated by a therapist or physician prior to initiating therapy, and routine spine films are necessary to rule out any contraindications. A CT or MRI is not a prerequisite before therapy, but most patients have undergone neuro-imaging. A trained VAX-D technician administers the daily therapy for approximately 20 sessions. The occasional patient may require a short maintenance period where 2 to 3 treatments a week are given for 2 to 4 weeks following initial therapy. The average patient has required 20-25 sessions. Each session is 15 cycles, each cycle being one minute of distraction and one minute of relaxation. Patients are instructed to wear loose clothing for each treatment. The patient is placed prone on the table such that the superior border of the pelvic harness is level with the split. The patient then grasps the adjustable handgrips, which are positioned to maintain the arms straight without bending the elbows. A small roll is placed under the patient's ankles; a chin or forehead roll is optional. Patients who have difficulty lying prone can use a pillow placed under the abdomen. Patients with shoulder pathology may employ a roll under the axilla. The patients are instructed to hold tightly to the handgrips, since motion artifact can be seen on the graph printout if the patients are pulling with their arms. This maneuver inhibits decompression. The patient is allowed to release their grip during the relaxation phase.

Figure 3A. Decompression formula: Exp (CN x Ln(BTi)) = BTn + (N x In)

A pretension level of 20 lbs. is set and maintained throughout the resting phase. Ramos 15 demonstrated that 50 pounds of tension was the threshold tension necessary to develop negative intradiscal pressures. Women start with 50 lbs and work up to 70 lbs of tension. Men usually start at 60 lbs and work up to 80 lbs. Tension increments are in the order of 5 pounds every 3-4 days, although some patients tend to proceed more slowly. Tension should remain constant for each treatment (figs. 2, 3 and 3B).

If the centralization phenomenon, the movement of a pain pattern from a distal to a more proximal location, occurs in the early treatment stages, the patient is most likely respond to physical therapy and not require further VAX-D. Centralization may appear at a later stage of treatment or shortly after completion of a full VAX-D course. In patients with an intact annulus, no researcher has yet reported the results of CT discography prior to treatment, and following the onset of centralization .4 Pain during distraction that lessens with relaxation is probably due to stretching shortened tissue. If pain persists for more than 30 minutes after treatment the tension should be reduced for the next few sessions. The tension should be lowered or the treatment cycle stopped for pain that increases with each 2-minute cycle. Some patients require a 2-3 day hiatus from therapy if they have too much discomfort. The daily response to treatment, and any changes made, are recorded in the patients chart and reviewed by the physician and technician every few days.

Figure 3B. Intradiscal pressure vs tension applied with VAX-D

Patients are encouraged to remain active but should not engage in strenuous activities while undergoing therapy. They should not be receiving any other treatment modalities while receiving VAX-D therapy. Patients may wear a back support after therapy, but it should be removed within 1 - 2 hours. Once the VAX-D course is completed, patients are encouraged to enter some form of rehabilitation program and learn proper biomechanics.

Discussion Ramos arid Martin 15 studied intradiscal pressures during VAX-D treatment. Five cases with subligamentous disc herniation at L4-5, confirmed by MRI and scheduled for percutaneous discectomy, were chosen. Using lateral and antero-posterior fluoroscopy, a cannula was inserted into the nucleus pulposus of the L4-5 intervertebral disc The pressure measurements were recorded by an Ohmeda pressure transducer connected to a Hewlett Packard pressure monitor via a saline bridge and a Camino fiberoptic intracranial transducer adapted for intradiscal measurements. Since the pressure transducers were designed to measure changes in the positive range, calibration was necessary. The pressure transducer and monitor for each patient were individually calibrated, and a correction curve was plotted showing the transducer readings versus actual pressures to correct for the nonlinearity of the instrumentation in the range of the negative pressures achieved. A pneumatic calibration analyzer was employed. Distraction tensions ranging from 50 to100 pounds were monitored on a digital readout and recorded on a continuous graph tracing by a chart printer incorporated in the control console. Intradiscal pressure changes were observed on the pressure monitor. Intradiscal pressures were significantly reduced to negative levels, ranging from 100 mm of Hg to a negative of 160 mm of Hg. Changes in intradiscal pressure were minimal until a threshold distraction tension was reached. The relationship between percentage maximum tension and time was a logarithmic function. If one plots the percentage of maximum tension reached in 60 seconds vs. time, it takes 17-20 seconds to reach 50%, 25-28 seconds to reach 70%, and 42-45 seconds to attain 90%

0 10 20 30 40 50 60 70 80 90 100 VAX-D APPLIED TENSION IN POUNDS

INT

RA

DIS

CA

L P

RE

SSU

RE

m

m H

G 100

0

-100

-150

75

of the maximum. The retraction phase followed a linear time/tension relationship and returned to baseline in 25-30 seconds. The first large-scale retrospective study7 involved over 700 patients with low back pain and with/ without radicular symptoms. Over 70% achieved a positive outcome. Even though the study was not a randomized blinded trial, the majority of patients were suffering beyond the period where natural resolution would be expected. All had failed treatment with other modalities and demonstrated positive response during treatment and/or immediately thereafter. Sherry et al19 conducted a prospective randomized controlled trial of VAX-D versus TENS. All patients had chronic symptoms (average duration of pain 7 years). TENS was regarded as a placebo. The data revealed an attributable success rate of 68.4% for VAX-D, significantly superior when compared to TENS (p<0.001).

A study by Ramos15 compared the effects of a sub-therapeutic treatment versus the protocol treatment. All patients had symptoms of sciatica and were referred to a neurosurgeon after failing conventional therapy. Imaging studies and the clinical examination were concordant. The protocol group demonstrated significantly superior results compared to the sub-therapeutic treatment group Two similar studies evaluating the effect of VAX-D on sensory dysfunction in cases of low back pain came to similar conclusions.14,22 Either Current Perception Threshold Neurometer or Dermatomal Somatosensory Evoked Potentials protocol was employed. Both studies demonstrated VAX-D capable of positively influencing sensory nerve dysfunction associated with compressive radiculopathy. Although compression is a frequent finding in sciatica compression does not explain all the observed symptomatology. Other factors include the force and rapidity of compression, the effect on arterial and circulation, and the release of pain, vascular, and neural modulators: nitrous oxide, phospholipase A2; the prostaglandins, and leukotnienes.3,6,16,17

Summary VAX-D should not be considered traction in the traditional sense but as decompression. VAX -D is the only non-invasive treatment that has been proven to decompress the disc; with other traction devices, there has only indirect proof. The patented therapeutic curve demonstrates that, when time is plotted against force, one observes a logarithmic function. Conventional traction devices have a linear time-force relationship. Non-steroidal anti-inflammatory drugs, steroids, and doxycycline have been given in conjunction with VAX-D therapy to study possible diffusion into the disc and any beneficial effects. Other concerns for the future include investigation of immunomodulators, transplanting fibroblast and chondrocytes, and minimally invasive surgical techniques in conjunction with VAX-D. The current focus may shift from treating back pain to repair and healing of a damaged disc.

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with herniated or degenerated disc or facet syndrome an outcome study. J Neuro Res 201W6490, 1998 8. Guenet RJ, Hadler NM,: Diagnosis and treatment of backache. Semin Arth Rheum 8: 261-267,1979 9. Haklius A Prognosis in sciatica: Acta Orthop Scand 129(Suppl): l-76, 1970 10. Janke AW, Kerkow TA, Griffiths HJ, et al. The biomechanics of gravity dependent traction of the lumbar spine. Spine 22: 253-260, 1997 11. Lancourt JE: Traction techniques for low back pain J Musculoskel Med 5: 44, 1986 12. MacKinney L: Medical Illustrations in Medieval Manuscripts, Wellcome, London, England, 1965 13. Nachemson A, Elfstrom G, Intravital dynamic pressure measurements in lumbar spine disc: Scand J Rehabil Med 1(Suppl): 5-40, 1970 14. Naguszewski W Naguszewski R, Gose E, Dermatosomal Somatosensory Evoked Potentials demonstration of nerve root decompression after VAX -D therapy. J.Neuro Res 23: 706,-714, 2001 15. Ramos G, Martin W, Effects of vertebral axial decompression on intradiscal pressure J Neurosurg 81: 350-353, 1994 16. Rydevik B, Brown M, Lundborg G: Pathoanatomy and pathophysiology of nerve root compression. Spine 9: 7-15, 1984 17. Saal JA, Dobrow R, Saal JF, et al: High levels of inflammatory phospholipase activity in lumbar

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